Considerable attention has been given to the development of apparatus for cutting elastic bands from tubular band stock and further for the application of cut elastic bands to various objects ranging from broccoli to stacks of envelopes. While it is possible in some installations to provide elastic band cutting apparatus which deposits the cut bands directly on the elastic band manipulating apparatus, in some applications such an arrangement is not possible or desirable. Moreover, there are many installations in which cut elastic bands are provided in bulk, which installations require the provision of apparatus for picking individual bands out of the bulk source of cut elastic bands. Once picked up by the band picking apparatus, the individually segregated bands must be transported from the band picker to the band expanding or manipulating apparatus.
Since band expanding and applying apparatus can operate at relatively high speed, and since band cutters similarly can operate at very high speed, it is important that any band transporting device must be capable of rapid cycling so that it does not become the bottleneck which limits overall system operation. The requirement for rapid operation, in turn, produces significant dynamic forces on the rubber band as it is transported between a band loading station proximate the source of bands to a band unloading station proximate the band manipulating apparatus.
Typical of apparatus suitable for cutting rubber bands from a continuous sheet of tubing are the devices disclosed in U.S. Pat. No. 4,579,027 to Lewis and U.S. Pat. No. 4,060,015 to Gros. The Gros patent further includes a band transport assembly in which a pair of tensioning fingers are inserted into the tubing and used to transport the cut band from the cutter to a band delivery position for further manipulation. The transport fingers in the patent to Gros control the orientation and path of the band during the dynamics of transport by placing the band under tension on the transport fingers.
U.S. Pat. No. 4,674,270 to Tonus also discloses a rubber band cutting assembly which has a transport arm with snagging pins that pierce the elastic band as it is cut from the band tubing. The cut bands are forced onto the snagging pins where they are held by the pins during rotation of the cut band to band expanding arms. Thus, the band is controlled during the dynamics of the transport process by impaling the band on diverging snagging pins.
Additionally, elastic band pick up assemblies have been devised which will pick up individual elastic bands from a bin having a plurality of cut bands in random orientations. The pick up device, in effect, combs through and segregates bands until it finally picks up an individual band on a finger and conveys the same to an unloading station proximate a band manipulating assembly, such as a band expander. Such pickup devices usually depend upon the use of a plurality of fingers in a conveyor which moves relatively slowly, with the number of fingers helping to reduce the cycle time at which bands reach the band expander. The band is maintained on the pick up fingers by gravity during the transport process.
Such prior elastic band transport apparatus have been found to have certain disadvantages. Systems which depend upon controlling the band by expanding the same, for example, the device in the patent to Gros, require a somewhat tedious insertion of the fingers into the band and expansion step to produce gripping of the band. These types of manipulations tend to slow cycling and complicate the required apparatus. The Tonus approach of piercing the band to secure the same on snagging pins has the disadvantage of not being well suited for use with thin bands. The piercing step endangers the integrity of thinner bands and can become impossible to use. The gravity support approach is usually applicable when the transport speeds are not very high and requires the use of multiple conveying fingers to try to increase the cycling rate.
Accordingly, it is an object of the present invention to provide an apparatus and method for rapid transport of cut elastic bands from a band loading station to a band unloading station which is suitable for use in a wide variety of applications.
Another object of the present invention is to provide an apparatus for the rapid transport of elastic bands which does not require gripping or expansion of the bands during the transport process.
Still a further object of the present invention is to provide an apparatus and method for the transport of elastic bands between a source of bands and band manipulating apparatus which is suitable for use with elastic bands of any width.
Still another object of the present invention is to provide an apparatus and method for rapid transport of elastic bands between a band cutting assembly and a band expanding assembly which is durable, reliable and simple in its construction and operation.
The elastic band transport apparatus and method of the present invention have other objects and features of advantage which will become apparent from and are described in more detail in the following description of the Best Mode Of Carrying Out The Invention and the accompanying drawing.